The invention relates to a piezoelectric acceleration transducer, in particular for use in safety systems for motor vehicles, comprising an assembly consisting of a flexible element which is made of a piezoelectric material and is provided with two external electrodes, and which is secured to a support, the entire assembly being mounted on a substrate or carrier plate. Acceleration transducers of this type are equipped with a flexible element made of piezoelectric material, typically a piezoceramic, as the sensor element, which is mechanically clamped to a reference point, or an arrangement of several such flexible elements. The flexible element is deflected by acceleration or other forces acting on it, producing a voltage at the electrodes of the flexible element as a result of the piezoelectric effect, the said voltage being proportional to the acceleration or other force.
For use in the safety equipment of motor vehicles, so-called series bimorphous flexible sensors are particularly suitable. They consist of an assembly of an even number of ceramic bars, the external faces of which are usually provided with highly electrically conductive coatings, thus forming the external electrodes. Knowledge exists as to how to arrange bimorphous flexible sensors of this type on a substrate mounted in a housing by means of a support, in such a way that the principal axis of sensitivity of the flexible element is perpendicular to the plane of the substrate. Since many motor vehicle manufacturers: require the printed circuit board carrying the evaluation electronics to be arranged in the same plane as the road, the said housing must be mounted to the printed circuit board in such a way that the principal axis of sensitivity lies in the same plane as the printed circuit board, i.e. the housing must be at a 90 degree angle relative to the substrate. This requires a high-cost assembly consisting, first, of a mechanical retaining device to establish the requisite connection between the housing and the printed circuit board and, secondly, or a comb-like conductive structure to produce an electrical connection between the terminal pins on the housing and the printed circuit board itself.